Ranking of
Web Services
Eyhab Al-Masri
Outline
1
Discovery of Web Services
2
Ranking of Web Services
3
Approaches
4
Conclusion
5
Q&A
Eyhab Al-Masri
Web Service Properties
 Self-Describing
 Service interaction must be well
defined through an interface
• Well Documented
• Human Readable
 Self-Discoverable
 Simple mechanism to publish info
 Easy way to find services
 Efficient way to interact with Web
services
Eyhab Al-Masri
Current Web Service Architecture
Service
Registry
Implements the
service and makes it
available over the
Internet
Consumer of a
service
Central directory for
publishing and
finding services
Service
Provider
Interact
Service
Consumer
Eyhab Al-Masri
UDDI Business Registry (UBR)
 UDDI:
 Universal Description, Discovery, and Integration
 Central location for publishing, managing, and
discovering Web services
 A focal point where all businesses of all sizes can
meet in an open, global framework
 As the number of Web services increase, the
success of businesses will depend on service
discovery
Eyhab Al-Masri
UDDI Business Registry (UBR)
 UBR APIs should be able to:
 Effective search functionality
 Enable clients to choose between two
implementations of Web service based on
quality of service metrics
 Provide multiple search techniques (i.e.
search by name, by category, contextual
information, etc…)
 Provide a mechanism for outputting
desired Web services
Eyhab Al-Masri
UDDI Business Registry (UBR)
UBR v 3.0 Current Status
Centralized or decentralized
Decentralized
Can Associate Web services specific
measurements?
No Standard mechanism
Abstract Level
Very Abstract
Search techniques
Very basic
Any guarantee to quality of published
information
No. Registration is voluntary
Range-based searching
No
Support for versioning
No
Caching?
No
Validate, govern, and secure Web
services?
No
Eyhab Al-Masri
UDDI Business Registry (UBR)
UBR
limitations
Clients will be unable
to distinguish Web
services from one
another
Depending on keyword
matching (which is very
limited), clients will be
flooded with results
Clients will take
longer to find relevant
Web services
Service providers
may not have enough
visibility
Eyhab Al-Masri
UDDI Business Registry (UBR)
Discovering Web services
will be less productive
Discovery results
become inaccurate
Discovering Web
services becomes
unreliable
Business collaboration
will not be cost effective
Limited
UBR
Features
Finding relevant Web
services will be very
time consuming
Locating information will be
a challenging task
“… UBR got passed around like a bad cold and it ended up hooking up with the wrong people…”
Miko Matsumura, Vice President Infravio Inc & Chair OASIS SOA Blueprints Technical Committee
From “Who Killed UBR” 2006 – SearchWebSevices.com
Eyhab Al-Masri
What is a possible solution?
 One apparent solution is to think of a way to
“differentiate” between Web services
 How ?
 Ranking
• Ranking is an important part of many information retrieval
systems
• Discovery of Web services involves the collection and
retrieval of information, therefore, a ranking mechanism
becomes extremely significant
Eyhab Al-Masri
Ranking of Web Services
As Web services proliferate:
I.
UDDI Business Registries will be filled with millions
of published Web services
http://haydn.cs.washington.edu:8080/won/wonServlet
Eyhab Al-Masri
Ranking of Web Services
II.
Decentralizing UBRs will add to the already existing
problem of finding relevant Web services
UDDI.org: UDDI Products and Components
Eyhab Al-Masri
Ranking of Web Services
III. Without a ranking mechanism, it will become very
common that search queries will return thousands if
not millions of results, a common dilemma faced
with regular Web searches.
Google.com’s search for “Web” keyword
Eyhab Al-Masri
Ranking of Web Services
IV. The nature of how service registries operate
makes the querying technique different from
the ones used on the Web and other
traditional information retrieval systems
UDDI.org (Service Discovery - - Section 2.1)
Eyhab Al-Masri
Approaches

QoS-based:


Measure QoS for Web services
Allow Clients to search for Web services by specifying QoS
parameters
•
(i.e. search for all Web services that have the keyword ‘weather’ in
Guelph with 99% reliability”)

Liu, Y., Ngu, A.H., Zeng, L., QoS computation and policing in
dynamic web service selection, Proceedings of the 13th
international World Wide Web conference on Alternate track
papers & posters, May 19-21, 2004, New York, NY, USA.

Zeng, L., Benatallah, B., Dumas, M., Kalagnanam, K., and
Sheng, Q.Z., Quality Driven Web Services Composition Proc.
12th Int'l Conf. World Wide Web (WWW), May 2003.
Eyhab Al-Masri
Approaches

Caverlee, J., Liu, L., and, Rocco, D., Discovering and ranking web
services with BASIL: a personalized approach with biased focus,
Proceedings of the 2nd international conference on Service
oriented computing, November 15-19, 2004, New York, NY, USA



Uses two distinct techniques:
 Categorization
 Personalized relevance
Ranks highly relevant data services and measures the relevance between services
using a series of biased probing methods .
E. Rahm and P. A. Bernstein. A survey on approaches to automatic
schema matching. VLDB Journal, 10(4), 2001.

tries to collected information about the semantics of the schemas, and
provide analysis based on them. Analysis includes:
•
•
•

linguistic analysis,
structural analysis,
domain knowledge
Lu, H., Semantic Web Services Discovery and Ranking, Web
Intelligence, 2005

Semantic discovery and ranking of Web services through a sequence
of types in its inputs and output variables and using a partial
matching technique
Eyhab Al-Masri
Conclusion
1
As the number of
Web services
increase, the
success of
businesses will
depend on service
discovery.
2
3
It is a crucial to provide
effective means to
distinguish between
Web services
particularly if they share
similar functionalities.
Providing a ranking
mechanism for Web
services is inevitable
and can significantly
enhance the
discovery process by
outputting desired
services within top
results.
Eyhab Al-Masri
Q&A